Wow, a lot of bolded text in this thread... 
51% is theoretical. Each node makes an independent choice of which chain to follow. We expect that full nodes will always follow the chain with longest proof-of-work, among valid chains (invalid chains will be rejected by all nodes). It can happen that two valid blocks are mined almost simultaneously. Rather than trying to figure out "which block was really mined first", the network just waits to see which block will get extended by the mining nodes. So, if A&B appear almost simultaneously, then the network will wait for C to appear - C must either extend A or extend B. This can happen multiple times and the network will handle it just fine, although affected transactions will be in an uncertain status until the chain is fully resolved. This is why large transactions need to wait at least 6 blocks (1 hour) to confirm.
Bitcoin mining is a lottery, a distributed lottery. You get lottery tickets by running mining equipment. The more mining equipment you run and the faster your mining equipment, the more tickets you are scratching. So, miners will build as many machines as is profitable given electricity price versus block reward + tx fees so they can scratch as many lottery tickets as possible.
There is no unfair advantage. You can mine Bitcoins for about $4k - just buy a mining rig and join a mining pool.
Regarding the item #4, forgive for being confused about how a Block get confirmed and awarded to a miner...I read somewhere that it would take 51% of nodes to confirm a block, but I think that 51% only applies to forks perhaps ?
51% is theoretical. Each node makes an independent choice of which chain to follow. We expect that full nodes will always follow the chain with longest proof-of-work, among valid chains (invalid chains will be rejected by all nodes). It can happen that two valid blocks are mined almost simultaneously. Rather than trying to figure out "which block was really mined first", the network just waits to see which block will get extended by the mining nodes. So, if A&B appear almost simultaneously, then the network will wait for C to appear - C must either extend A or extend B. This can happen multiple times and the network will handle it just fine, although affected transactions will be in an uncertain status until the chain is fully resolved. This is why large transactions need to wait at least 6 blocks (1 hour) to confirm.
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I'm still trying to figure that if it is possible that miners to win rewards purely base on randomness- like a lottery, rather than base on how expensive, and high power equipment...essentially leveling the playing field.
Bitcoin mining is a lottery, a distributed lottery. You get lottery tickets by running mining equipment. The more mining equipment you run and the faster your mining equipment, the more tickets you are scratching. So, miners will build as many machines as is profitable given electricity price versus block reward + tx fees so they can scratch as many lottery tickets as possible.
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Wouldn't that eliminate the unfair advantage of large mining companies vs smaller individual miner ? And decentralize the mining portion of blockchain ? I just don't think adjusting the difficulty level is the most sufficient way to confirm blockchain ?
There is no unfair advantage. You can mine Bitcoins for about $4k - just buy a mining rig and join a mining pool.